DESCRIPTION: Organophosphate (OP) pesticides are highly toxic compounds used to control insect populations in a number of agricultural and landscaping applications. The widespread use of these toxic chemicals has generated serious environmental health risks. It is vital to sensitively and accurately bio monitoring of environmental exposure to OP pesticides and assessment of its health risk. However, simple, rapid, and quantitative diagnostic technologies and devices for detecting environmental OP exposure are not available. This Small Business Innovation Research Project is to develop a handheld bio monitoring device incorporating a functionalized nanoparticle and a lateral flow test strip for simple, rapid, cost-effective, and quantitative detection of environmental exposure to OP using a blood sample. This project takes advantage of phosphorylated cholinesterase (OP-ChE) as a biomarker of OP exposure. In phase I, there are three specific aims: (1) Develop Zr (IV)-functionalized fluorescence nanoparticles (Zr-FFNPs) that bind to OP-ChE. (2) Develop a Zr-FFNP-based new immunoassay for detecting OP-ChE. (3) Adapt the Zr-FFNP-based immunoassay to a lateral flow test strip system for detecting OP-ChE. The research will determine the detection limits, response time, dynamic range, and other key performance metrics of the device using blood samples in vitro dosed with three typical pesticides and prove the feasibility of the handheld bio monitoring device for sensitively detecting OP exposure. Phase II will further develop a specialized hand-held bio monitoring device for detecting exposure to OP. The device will be validated with blood in vitro dosed with a wide range of OP pesticides and blood samples from students in schools near farms and family members of workers who involved in the used of OP pesticides. The portable biomonitoring device developed under this program will provide a point-of-care tool for rapid, sensitive, cost-effective, and real-time detection of environmental exposure to OP pesticides.